|Number|Year built|Livery|Current status|Notes|
|---|---|---|---|---|
|2|1964|Red and white|Operational|Based on a Metropolitan Tramway style open-topper|
|4|1961|Blackpool Tramway green and cream|Operational|Based on a Blackpool style Open Boat|
|6|1954|Green and cream|Operational|Based on a Llandudno & Colwyn Bay style open-topper|
|7|1958|Brown and cream|Stored awaiting overhaul|Based on a Llandudno & Colwyn Bay style open-topper|
|8|1968|Bristol blue and white|Operational|Based on a Llandudno & Colwyn Bay style open-topper|
|9|2002|Two tone blue|Operational|Based on design elements from Plymouth and Blackburn tramcars|
|10|2002|Orange, green and cream|Operational|Based on design elements from Plymouth and Blackburn tramcars|
|11|2002|Pink|Operational|Based on design elements from Plymouth and Blackburn tramcars|
|12|1966|Currently being repainted into London Transport red and cream|Operational|Based on a London Feltham-type tram|
|14|1904|Red and white|Operational|Ex Metropolitan Tramways 94. Rebuilt into its current format in 1984|
|16|1921|Crimson and yellow|Operational|Ex Bournemouth 106. Rebuilt into its current format in 1992|
|17|1988|Red and white|Operational|Based on a Manx Electric Railway toastrack tram|
|19|1906|Green and white|Operational|Ex Exeter 19. Rebuilt into its current format in 1998|

Question: how many cars are based on the plymouth and blackburn tramcars?
Answer: 3